Discussion: “Theory Versus Experiment for the Rotordynamic Coefficients of Annular Gas Seals: Part 2—Constant-Clearance and Convergent-Tapered Geometry” (Nelson, C. C., Childs, D. W., Nicks, C., and Elrod, D., 1986, ASME J. Tribol., 108, pp. 433–437)